An avalanche photodiode quenching circuit (20) incorporates an avalanche
photodiode (APD) (22) and a first comparator (C1) responsive to reduction
in APD voltage. The comparator (C1) is arranged to activate an APD quench
circuit (38) in response to APD avalanche initiation. The circuit (20)
also includes a second comparator (C2) arranged to reset the first
comparator input (N2) in response to a further reduction in APD voltage
caused by initiation of quenching. The second comparator (C2) is also
connected to a monostable circuit (48) arranged to latch the first
comparator output response to resetting. The monostable circuit (48)
maintains the first comparator output level constant until the APD (22)
has recharged.
Other References
Applied Optics, vol. 26, No. 12, Jun. 15, 1987, New York, U.S., R G. W.
Brown et al, "Characterization of Silicon Avalanche Photodiodes for Photon
(con't) Correlation Measurements. 2: Active Quenching", pp. 2383-2389.
|